Method and apparatus for tissue ablation

ABSTRACT

A method for ablation in which a portion of atrial tissue around the pulmonary veins of the heart is ablated by a first elongated ablation component and a second elongated ablation component movable relative to the first ablation component and having means for magnetically attracting the first and second components toward one another. The magnetic means draw the first and second components toward one another to compress the atrial tissue therebetween, along the length of the first and second components and thereby position the device for ablation of the tissue.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/411,261, filed Apr. 26, 2006, which is a continuation of U.S. patentapplication Ser. No. 10/756,437, filed Jan. 13, 2004, now U.S. Pat. No.7,094,235, which is a continuation of U.S. patent application Ser. No.10/016,297, filed Dec. 12, 2001, now U.S. Pat. No. 6,699,240,incorporated herein by reference in their respective entireties. Thisapplication also claims priority from U.S. Provisional PatentApplication No. 60/286,953, filed Apr. 26, 2001, incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to surgical tools and procedures generallyand relates more particularly to the use of ablation to treat atrialfibrillation and other disorders.

In patients with chronic atrial fibrillation having tachycardia thatresistant to medical treatment, the Maze procedure has been employed.This procedure controls propagation of the depolarization wavefronts inthe right and left atria by means of surgical incisions through thewalls of the right and left atria. The incisions create blind or deadend conduction pathways, which prevent re-entrant atrial tachycardiasfrom occurring. While the Maze procedure is successful in treatingatrial fibrillation, the procedure is quite complex and is currentlypracticed by only a few very skilled cardiac surgeons in conjunctionwith other open-heart procedures. The procedure also is quite traumaticto the heart, as in essence the right and left atria are cut into piecesand sewn back together, to define lines of lesion across which thedepolarization wavefronts will not propagate.

It has been suggested that procedures similar to the Maze procedurecould be instead performed by means of electrosurgical ablation, forexample, by applying RF energy to internal or external surfaces of theatria to create lesions across which the depolarization wavefronts willnot propagate. Such procedures are disclosed in U.S. Pat. No. 5,895,417,issued to Pomeranz, et al., U.S. Pat. No. 5,575,766, issued to Swartz,et al., U.S. Pat. No. 6,032,077, issued to Pomeranz, U.S. Pat. No.6,142,944, issued to Swanson, et al. and U.S. Pat. No. 5,871,523, issuedto Fleischman, et al, all incorporated herein by reference in theirentireties. Hemostat type electrosurgical or cryo-ablation devices foruse in performing such procedures are described in U.S. Pat. No.5,733,280 issued to Avitall, U.S. Pat. No. 6,237,605 issued to Vaska, etal, U.S. Pat. No. 6,161,543, issued to Cox, et al., PCT publishedApplication No. WO99/59486, by Wang and in pending U.S. patentapplication Ser. No. 09/747,609 filed Dec. 22, 2000 by Hooven, et al.,all incorporated herein by reference in their entireties. In order forsuch procedures to be effective it is desirable that theelectrosurgically created lesions are continuous along their length andextend completely through the tissue of the heart. In order for suchprocedures to be effective it is desirable that the electrosurgicallycreated lesions are continuous along their length and extend completelythrough the tissue of the heart. Analogous issues arise when attemptingto create continuous lines of lesion through the walls of other heartchambers or other organs.

SUMMARY OF THE INVENTION

According to the present invention elongated lesions as might be desiredin a maze type procedure or other procedure may be produced using a setof two elongated ablation components carrying means (e.g. an electrodeor electrodes) for applying ablation energy (e.g. RF energy) along itslength. The ablation components are adapted to be arranged on oppositesides of the walls of the atria or other hollow organs, on either sideof the organ walls and to ablate or create lesions in the tissue betweenthe components. The ablation components may also be arranged alongopposing external surfaces of an organ, for example opposite sides of anatrial appendage or along opposite sides of the tissue adjacent thebases of the right or left pulmonary veins.

The ablation components are provided with a magnetic system for drawingthe components toward one another to compress the wall or walls of anatrium or other hollow organ therebetween, along the length of thecomponents. In these systems, at least one of the components is providedwith a magnet or series of magnets extending along the component. Theother component is provided with a ferromagnetic member or preferablyanother magnet or series of magnets extending along its length, havingpolarity chosen to assure attraction between the two components. Themagnet or magnets may be rigid or flexible and may be formed of magneticmaterial, e.g. rare earth magnets, or may alternatively beelectromagnets.

In one preferred embodiment of the invention, the two componentscomprise opposing jaws of an electrosurgical hemostat, provided withelongated RF electrodes and having straight or curved configurations. Insome of these embodiments, the jaws of the hemostat are both rigid andthe magnets are present primarily to assure good contact and alignmentbetween the jaws, along their length. In other embodiments, one jaw maybe rigid and the other flexible, for example to allow it to betemporarily deformed to access desired locations. In these embodiments,magnetic system also assists the flexible jaw in returning to aconfiguration corresponding to the rigid jaw, as the jaws are broughtinto proximity to one another. In some embodiments, one jaw may beshapeable, so that the physician can select a desired configuration,with the other jaw being flexible. In these embodiments, the magneticsystem allows the flexible jaw to automatically assume a configurationcorresponding to the shapeable jaw. In other embodiments, both jawsmight be flexible.

Similar sets of embodiments may be provided wherein the two componentsare separate from one another, for example mounted to separate handles.Alternatively, a first, external component might be mounted to a handle,to he held by the physician, while a second, internal component may belocated on a percutaneously introduced catheter. In these embodiments,the internal component would typically be quite flexible, while theexternal component would be either rigid or shapeable. In theseembodiments the magnetic system allows the internal component toautomatically assume a configuration corresponding to the externalcomponent, after introduction of the internal component to the interiorof the hollow organ.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of hemostat of the type in which the presentinvention may be embodied.

FIGS. 2A through 2G illustrate alternative configurations for the jawsof the hemostat of FIG. 1, illustrating alternative embodiments of thepresent invention in cross section and longitudinal section.

FIG. 3 is a perspective view of a hemostat of a second type, in whichthe present invention may be usefully practiced.

FIG. 4 is an illustration of a system employing the invention, includinga first external component and a separate second internal component.

FIGS. 5A through 5D illustrate alternative embodiments of the distalportion of the internal component illustrated in FIG. 4, in crosssection and longitudinal section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a plan view illustrating a bipolar electrosurgical hemostat ofa type in which the present invention may usefully be practiced. Thehemostat is provided with handles 14 and 12, coupled to pivoting jaws 16and 18, respectively. Located along jaws 16 an 18 are ablationelectrodes 20 and 22, which, as discussed below, take the form of RFelectrodes. In alternative embodiments, electrodes 20 and 22 may beemployed to apply microwave radiation, or might be replaced by elongatedheating or cooling elements to provide for thermal or cryo-ablationalong their length. In the embodiment illustrated, the electrodes areirrigated RF electrodes, allowing for delivery of saline or otherconductive fluid along their lengths, generally according to themechanism as described in U.S. Pat. No. 6,096,037 issued to Mulier,incorporated herein by reference in its entirety. Each electrode isprovided with a fluid delivery lumen 30, 32, through which the saline orother conductive fluid is delivered to the electrodes. Lumens 30 and 32are coupled to a luer fitting 34, which may be coupled to a source ofconductive fluid. Separate luer fittings for each of lumens 30, 32 mightalternatively be provided. Similarly, each electrode is provided withconductors 24, 26 allowing the electrodes to be coupled to a source ofablation energy via electrical connector 28, as noted above. The sourceof ablation energy may provide RF energy or microwave energy. Inalternative embodiments in which electrodes 20 and 22 are replaced byheaters, the fluid delivery lumens may not be provided, and instead,electrical conductors 24 and 26 may be coupled to two elongatedresistive heaters arranged along jaws 16 and 18, and coupled to anelectrical power source via connector 28. In alternative embodiments inwhich elongated cooling elements are substituted for electrodes 20 and22, cooling fluid might be delivered to electrodes via fluid lumens 30and 32 or alternatively, in the event electrical cooling devices areprovided, electrical power might be delivered to the cooling devices viaconnectors 24 and 26 through electrical connector 28.

While the discussion below focuses on ablation systems in which theparticular ablation energy delivered is RF energy, delivered viairrigated electrodes, it should be understood that the present inventioncan usefully be practiced in conjunction with the other forms ofablation energy referred to above. As such, for purposes of thefollowing discussion, the illustrated and described irrigated RFelectrodes should be taken as exemplary of a mechanism for applyingablation energy according to the present invention, rather than aslimiting.

Jaws 16 and 18 may have a straight configuration as illustrated, or maybe curved. Jaws 16 and 18 are preferably manufactured of anon-ferromagnetic material such a biocompatible plastic, and, asdiscussed below, carry an elongated magnet or series of magnets,extending along the electrodes 20 and 22, in order to assist in aligningthe electrodes relative to one another on opposite sides of tissue to beablated and to assist in compressing tissue between the electrodes toassure good contact along their length. As described in more detail,jaws 16 and 18 may be rigid, shapeable, or flexible, depending on theparticular embodiment of the invention being practiced.

FIGS. 2A through 2G illustrate various alternative embodiments of theinvention, employing different types of magnetic alignment systems anddifferent configurations for the first and second components (in thiscase the jaws 16 and 18), along which ablation energy is to be applied.FIG. 2A illustrates a cross sectional view through jaws 16 and 18 of thehemostat of FIG. 1, in which the electrodes 20 and 22 take the form ofelongated electrode coils 100, 102, respectively, carrying internalporous tubes 104 and 106. Tubes 104 and 106 may be fabricated, forexample, of porous polytetrafluoroethylene (PTFE), and have theirinternal lumens coupled to the fluid lumens 30 and 32 illustrated inFIG. 1. By this mechanism, delivery of conductive fluid such as salinesolution along the length of the electrode coils 101 and 102 may beaccomplished. While as described, the electrodes 20 and 22 each includea single elongated electrode coil embodiments in which the components(jaws 16 and 18) are provided with multiple electrodes arranged alongtheir length are also within the scope of the present invention.

As illustrated, jaws 16 and 18 are each provided with a pair of magnetsor a series of magnets 108, 110, 112, 114, which extend along the jaws16 and 18. These magnets, shown in cross section, may either beindividual elongated magnets or may be a series of shorter magnets,extending along the jaws. The polarities of magnets correspond to the“N” and “S” markings as illustrated, arranged such that the jaws 16 and18 are attracted to one another along their lengths. Provision ofmagnets on both sides of the electrodes 18 and 20 assist in assuringthat the electrodes will center themselves with respect to one anotherso that the electrodes will be located directly across from one anotherwhen placed on opposite sides of tissue to be ablated. The magnets alsoassist in compressing the jaws of the hemostat along their length,assuring good contact with the tissue along the length of the jaws.

Jaws 16 and 18 are preferably fabricated of a non-ferromagneticmaterial, such as a plastic, so that the magnets and electrode coils asillustrated may be insulated from one another. In some embodiments, bothjaws 16 and 18 may be rigid and may be pre-formed with the sameconfiguration so that they are parallel to one another. Alternatively,one of jaws 16 and 18 may be rigid, while the other of the two jaws maybe quite pliant or flexible, so that upon placement of the jaws oneither side of the wall of a hollow organ to be ablated, the magneticforce provided by the magnets causes the flexible jaw to assume aconfiguration parallel to the rigid jaw and to compress the wall of thehollow organ between the jaws. In additional alternative embodiments,one of the two jaws 16 and 18 may be shapeable by the physician, toassume a desired configuration, with the other of the two jaws beingflexible. In this embodiment as well, the flexible jaw is aligned andconfigured parallel to the shapeable jaw when the two jaws are broughttowards one another on either side of the wall of the hollow organ to beablated. The shapeable jaw may be shapeable by virtue of the materialchosen to fabricate the jaw, or means of a shapeable insert, forexample, a longitudinally extending rod of nitinol, stainless steel, orother shapeable metal, not illustrated in FIG. 2A.

FIG. 2B illustrates an alternative embodiment of an invention accordingto the present invention, similarly showing a cross section through jaws16 and 18 of the hemostat of FIG. 1. All elements correspond toidentically numbered elements in FIG. 2A. In this embodiment, only asingle elongated electrode or line of electrodes 116, 118 is providedfor each of the two jaws 16, 18 respectively. This configuration allowsfor a reduction in the overall size of the jaws, but otherwise functionsas described in conjunction with FIG. 2A. In FIG. 2B, an optionalmetallic shaping wire 120 is shown, mounted adjacent to the magnet ormagnets 118, to allow the physician to shape jaw 18. In embodiments inwhich this shaping wire is present, it is to be expected that jaw 16would be flexible, and would conform to the configuration provided tojaw 18 by the physician, after placement of the jaws on opposite sidesof tissue to be ablated.

FIG. 2C illustrates a third alternative embodiment of the presentinvention, also taking the form of a cross section through jaws 16 and18 of the hemostat of FIG. 1. Identically, numbered componentscorrespond to those illustrated in FIG. 2A. In this embodiment,elongated magnets or series of magnets 122 and 124 are located withinthe porous fluid lumens 106 and 104, so that magnetic force applied todraw the jaws 16 and 18 toward one another is applied centered withrespect to the electrode coils 100 and 102. The various alternativeembodiments discussed above in conjunction with FIGS. 2A and 2B maycorrespondingly be provided in conjunction with the jaws having thegeneral configuration illustrated in FIG. 2C.

As illustrated in 2A, 2B and 2C, the magnets are arranged so that thesouth pole(s) of the magnet(s) of one jaw are adjacent to the northpole(s) of the magnet(s) of the other jaw. This configuration will bemost desirable in conjunction with embodiments in which single,elongated magnets extend essentially along the length of the jaws, andalso in embodiments in which a series of shorter, closely spaced magnetsextending along the jaws is provided. In embodiments in which magnetsextend along the jaw but are more substantially spaced from one another,the polarity of the magnets may be altered, so that along one jaw, thenorth poles of the magnets may be located at the distal ends of themagnets and the south poles located at the proximal ends wherein on theother jaw, the south poles of the magnets will be located at theirdistal ends and north poles of the magnets will be located at proximalends. Alternative magnetic configurations such as this may be employedin any of the embodiments illustrated in FIGS. 2A, 2B and 2C in whichthe magnets take the form of series of spaced, magnets, running alongthe lengths of the jaws.

The magnets themselves may be of any appropriate magnetic material. Oneparticularly desirable set of magnetic materials for use in the presentinvention may be rare earth magnets, due to their extraordinary strengthfor relatively small sizes and weights. However, elongated flexiblemagnets might be substituted, as well as ceramic magnets. In addition,as discussed in more detail below, the magnets may be replaced withelectromagnetic coils. In further alternative embodiments, it may bepossible to employ magnets located in only one of the jaws, substitutinga ferromagnetic material such as magnetic stainless steel for the otherof the two magnets. For example, in the embodiment illustrated in FIG.2A, magnets 108 and 110 might be replaced be elongated magneticstainless steel members. In such an embodiment, the elongated stainlesssteel members would be attracted to the magnets 112 and 114 as describedbelow and might also be employed to provide the ability to shape the jaw116 to a desired configuration. Similar substitutions of non-magnetizedferromagnetic materials for the magnets illustrated in FIGS. 2B and 2Care also believed within the scope of the present invention.

FIG. 2D is a longitudinal sectional view through jaw 18 of the hemostatof FIG. 1. In this embodiment, the magnets 112 and 114 take the form ofa series of magnets, mounted within the body of jaw 18. Electrode coil102 and fluid lumen 106 are also illustrated in longitudinal section.

FIG. 2E illustrates an alternative longitudinal sectional view throughjaw 18, otherwise as illustrated in FIGS. 1 and 2A. Componentscorresponds to identically numbered components in FIG. 2A. In thisembodiment, however, jaw 18 is provided with indentations 126 in betweenthe individual magnets 114 and 112. These indentations, in conjunctionwith fabrication of the jaw 18 of the flexible material, define hingepoints, facilitating bending of the jaw 18. Such a configuration will beparticularly desirable in the event that jaw 16 as illustrated in FIGS.1 and 2A were to be made rigid or shapeable, with jaw 18 being flexibleenough to adapt to the configuration of jaw 16, when placed on theopposite side of tissue to be ablated.

FIG. 2F is a longitudinal sectional view through a hemostat having a jawconfiguration as illustrated in FIG. 2C. Components correspond toidentically numbered components in FIG. 2C. In this view, the magnet 122takes the form of a series of magnets located within fluid lumen 104.

FIG. 2G illustrates a longitudinal section through an embodiment of thepresent invention having a jaw configuration as illustrated in FIG. 2B.In this embodiment, the magnet 118 take the form a series of magnets118, located along side the shaping wire 120. Electrode coil 102 andfluid lumen 104 are also visible.

In the embodiments of FIGS. 2D, 2F and 2G, it should be understood thatelongated continuous magnets, flexible or rigid might be substituted fora series of individual magnets as illustrated. In addition, it shouldalso be understood that in some embodiments, the magnets as illustratedmight be more widely spaced from another, and arranged so that theirnorth/south magnetic access extends longitudinally along the lengths ofthe jaws, as described above in conjunction with FIGS. 2A through 2C. Insuch embodiments, the north/south magnetic axes of the magnets in onejaw would be opposite those of the magnets in the other jaw. Jawsemploying this arrangement of magnets might also be used in conjunctionwith a jaw or other ablation component taking the form of a series ofelectro magnets, for example, coils having their axes extending alongthe axes of the jaws or other ablation components.

FIG. 3 is a perspective view of a bipolar electrosurgical hemostat of asecond type, appropriate for use in conjunction with the presentinvention. In this embodiment the hemostat is provided with handles 212and 214 and elongated jaws 216 and 218. In this case, jaw 218 carries acircular ablation component 238, along which an electrode 220 isarranged. Jaw 216 is provided with a hook shaped ablation component 236,carrying a corresponding electrode facing electrode 220. The instrumentof FIG. 3 is particularly adapted for ablations and circling the basesof the pulmonary veins, in the context of an electrosurgical procedureanalogous to a maze procedure as discussed above. In this embodiment, itmay be desirable that the circular ablation component 238 is eitherrigid or shapeable by the physician, to allow adaptation of theconfiguration of the component to this particular anatomy of the patientinvolved. Component 236 is preferably at least flexible enough to bespread open slightly to facilitate placing of the jaw around the basisof the pulmonary veins and may be quite flexible, relying on themagnetic attraction between components 236 and 238 and to causecomponent 236 to assume a configuration parallel to component 238. As inconjunction with the hemostat illustrated in FIG. 1, fluid lumens 230and 232 are provided to allow delivery of a conductive fluid to theelectrodes, via luer fitting 234. Electrical conductors 224 and 226 areprovided to conduct electrical energy to the electrodes, via electricalconnector 228. As discussed above in conjunction with the hemostat ofFIG. 1, alternative means for applying ablation energy such as microwaveantenna or heaters or coolers to provide thermal or cryo-ablation may besubstituted for the electrodes.

FIG. 4 illustrates an additional alternative embodiment of theinvention, in which the two ablation components are separate from oneanother rather than being joined as in the hemostats of FIGS. 1A and 3.In this embodiment, the first component corresponds generally to jaw 216of the hemostat of FIG. 3, provided in this case with a handle 312allowing the physician to manipulate the device. An electrode 320extends around the curved ablation component 318, and may be, asdiscussed above, an irrigated electrosurgical electrode, provided withfluid via lumen 332 and luer fitting 334 and provided with electricalpower via conductors 326 and electrical connector 328. In use, thecurved ablation component 318 will be placed on the exterior surface ofthe organ to be ablated, for example, placed around the bases of apatient's pulmonary veins. In this particular embodiment, the curvedablation component 318 is preferably rigid or malleable, as the internalablation component 304, as discussed below, will be quite flexible.

The internal ablation component 304 takes the form of a catheter havingan elongated catheter body 414 carrying an electrode along its distalportion 420. Distal portion 420 may have a structure correspondinggenerally to the illustrated structures for the jaws of the hemostats asillustrated in FIGS. 2A through 2G, with the caveat that the structureof a distal portion 420 of the catheter should be fabricated of asufficiently flexible material that it may be introduced percutaneouslyand navigated to the desired location within the organ to be ablated.For example, the catheter might be advanced through the vascular systemto the interior of the left atrium, to a position adjacent the openingsinto the pulmonary veins. Alternatively, as illustrated in FIGS. 5Athrough D below, the distal portion 420 of the catheter may bespecifically optimized for location at the distal portion of a catheter.As illustrated, the proximal end of the catheter is provided with afitting 416 carrying a fluid coupling 434 allowing delivery of saline orother conductive fluid to the electrode located along the distal portion420 of the catheter. Electrical power is provided to the electrode bymeans of conductors 426 and connector 428 in a fashion analogous to thatdescribed above for the other embodiments.

FIGS. 5A-5D illustrate various alternative configurations for the distalportion 420 of the catheter 304 illustrated in FIG. 4. The embodimentsof the invention as illustrated in FIGS. 5A-5D may also be employed inexternal ablation components as illustrated in FIG. 4 or in hemostattype devices as illustrated in FIGS. 1 and 3.

FIG. 5A is cross sectional view through the distal portion 420 of thecatheter illustrated in FIG. 4, showing a first embodiment of inventionparticularly optimized for use as part of a percutaneously introducedcatheter. In this embodiment, the outer surface of the distal portioncomprises a porous tube 404, which may be made of PTFE as discussedabove, surrounding an electrode coil 402. A magnet or series of magnets406 is mounted within the lumen of the electrode coil 402. In thisembodiment, fluid is delivered through the lumen of the electrode coil402, permeates through the porous wall of tube 404, and electricalenergy provided by electrode 402 is coupled to the tissue to be ablatedvia the conductive fluid in the wall and on the surface of tube 404. Asillustrated, the electrode is shown having its magnetic polarity suchthat its north/south axis runs transverse to the axis of the catheter.However, alternative embodiments employing a series of spaced magnetshaving their north/south axis running along the axis of the catheter arealso within the scope of the invention.

FIG. 5B shows an alternative cross section through the distal portion420 of the catheter FIG. 4. Numbered elements correspond to identicallynumbered elements in FIG. 5A. In this embodiment, however, a shapingwire 410 is shown, allowing the physician to provide a desiredconfiguration to the distal portion 420 of the catheter. For example,the catheter may be biased to assume a generally circular configuration,which is straightened during the passage of the catheter through thevascular system, with shaping wire 410 allowing it to resume its desiredconfiguration when no longer retrained by vascular system.

FIG. 5C shows an additional alternative cross section through the distalportion 420 of the catheter FIG. 4. Numbered elements correspond toidentically numbered elements in FIG. 5A. In this embodiment, coil 412,however is not an ablation electrode but instead is employed as anelectromagnet to attract the catheter to an associated external ablationcomponent. Delivery of ablation energy, e.g. RF or microwave, isaccomplished by central wire 418.

FIG. 5D shows a longitudinal sectional view through the distal portion420 of a catheter having a cross section as illustrated in FIG. 5C.Numbered elements correspond to identically numbered elements in FIG.5C. In this view it can be seen that coil 412 is one of a series ofspaced electromagnet coils spaced along the distal portion 420 of thecatheter. As illustrated, coils 412 are wired in series, however, inalternative embodiments they may be wired for individual activation.

1. A method of ablating tissue comprising: selecting a first elongatedablation component carrying a longitudinally extending first means fordelivery of ablation energy and a second elongated ablation componentand movable relative to the first ablation component, wherein the firstand second components are provided with means mounted to and extendingalong the first and second components for magnetically attracting thefirst and second ablation components toward one another along the lengthof the first means for delivery of ablation energy; placing selected oneof the first and second components along a first portion of tissue ofthe atrium on an external portion of the heart adjacent one or morepulmonary veins; placing the other of the first and second componentsalong a second portion of tissue of the atrium on an external portion ofthe heart adjacent the one or more pulmonary veins to allow themagnetically attracting means to draw the first and second componentstoward one another to compress the first and second portions of tissuetherebetween, along the length of the first and second components; andapplying ablation energy.
 2. A tissue ablation method comprising:placing a first microwave ablation component on a first portion oftissue of a hollow organ; placing a second component on a second portionof tissue of the hollow organ, wherein the second component is coupledto the first component, wherein the first and second components aremagnetically attracted toward one another to compress the first andsecond portions of tissue therebetween; applying microwave ablationenergy to the tissue therebetween to create an ablation lesion.
 3. Amethod as in claim 2 wherein the hollow organ is a heart or portionthereof.
 4. A method as in claim 2 wherein the first portion of tissueis a portion of atrial tissue.
 5. A method as in claim 2 wherein thesecond portion of tissue is a portion of atrial tissue.
 6. A method asin claim 2 wherein the first portion of tissue is a portion of tissueadjacent the base of a pulmonary vein.
 7. A method as in claim 2 whereinthe second portion of tissue is a portion of tissue adjacent the base ofa pulmonary vein.
 8. A method as in claim 2 wherein the first or secondcomponent comprises a rare earth magnet.
 9. A method as in claim 2wherein the first or second component comprises an electromagnet.
 10. Amethod as in claim 2 wherein the first or second component comprises arigid portion.
 11. A method as in claim 2 wherein the first componentcomprises a rigid portion and the second component comprises a flexibleportion, wherein the flexible portion is sufficiently flexible to bemagnetically deflected into alignment with the first component.
 12. Amethod as in claim 2 wherein the first and second components arepivotally coupled to one another.
 13. A method as in claim 2 wherein thefirst and second components comprise jaws of a hemostat.
 14. A method asin claim 2 wherein one of the first and second components is providedwith a pre-formed curve portion.
 15. A method as in claim 2 wherein eachof the first and second components is provided with a pre-formed curveportion.
 16. A method as in claim 2 wherein the second component is asecond ablation component for delivery of an ablation energy.
 17. Atissue ablation device comprising: a first microwave ablation componentfor delivery of microwave energy, the first component comprising a firstmagnetically attractive element, a portion of the first component beingmanually shapeable; and, a second component comprising a secondmagnetically attractive element for magnetically attracting the firstand second components toward one another, the second component coupledto the first component; a portion of the second component beingsufficiently flexible to be deflected into alignment with the firstcomponent by the magnetically attractive elements.
 18. A system as inclaim 17 wherein second component is a second ablation component fordelivery of an ablation energy.
 19. A system as in claim 17 wherein atleast one of the magnetically attractive elements comprises a rare earthmagnet.
 20. A system as in claim 17 wherein at least one of themagnetically attractive elements comprises an electromagnet.
 21. Asystem as in claim 17 wherein the first and second components arepivotally coupled to one another.
 22. A system as in claim 17 whereinthe first and second components comprise jaws of a hemostat.